In mid-October, Brent Dmitruk told his tens of thousands of social media followers that an earthquake would soon hit at the westernmost point of California.
Two months later, a magnitude 7.3 struck the site in northern California - putting millions under a tsunami warning and growing Mr Dmitruk's following online as they turned to him to forecast the next one.
So, is Mr Dmitruk a seismology genius, a shamen - or shyster?
Eleanor Dunn is PhD Researcher at the Dublin Institute for Advanced Studies. She joins Seán to discuss.
Image: SEIS